Annealing furnace



March 27, 1934. 1.. wlLsoN 1,952,402

ANNEALING FURNACE Filed July 25, 1955 2 She'etS-Sheet l March 27, 1934.L. WILSON ANNEALING FURNACE Filed July 25, 1933v INV TOR ATToR N EYPatented` 27,1 1934 1,952,402 ANNEALING FUBNACE Lee Wilson, Cleveland,Ohio Application July 25, 1933, Serial No. 682,092

9 Claims.

This invention relates broadly to annealing furnaces, and moreparticularly to a furnace for heat treating or annealing metal sheets,strips, coils, plates, and the like, in-a controlled and non-oxidizingatmosphere. Y

The present invention aims to provide a fur nace in which the materialmay be efficiently heat treated or annealed by exposing the same in thefurnace, free from any covering whatsoever, in an atmosphere heated byradiation and free of products of combustion or other harmful gases.

A further object of the invention is to. provide a furnace in which thematerial may be treated in a fraction of the time consumed underexisting methods and with present structures, the.

annealing also being accomplished with the consumption of a minimumamount of fuel.

A further object is to provide individually con-` trolled heat radiatingunits for regulating the temperature of the furnace, as may be desired.

erence being had to the accompanying drawings,

in which- Figure 1 is a vertical cross sectional view of a furnaceconstructed in accordance with my lnvention, the section being taken online A-A, Fig. 3;

Figure 2 is a vertical cross sectional view' of the removable bell orhood removed from the stationary base or foundation, a portionbeingbroken away; and- Figure 3 is a section on line B-B, Fig. 1.v

The furnace is preferably composed of two principal parts- 'permanentbase or foundation, and a mova le bell or muille type heating furnace.

The base is permanently and stationarily constructed on the floor leveland consists of a foundation 1 of common brick upon which issuperimposed the base 2, the latter being made of an appropriateinsulating material. This construction provides a raised platform,rectangular in top plan view and wh'ose plane dimensions are greaterthan the sheets 3 to be annealed. AEncircling said base and at a spaceddistance therefrom is a U-shaped channel 4, designed to contain oil,water, molten lead, or other appropriate sealing agent. l

The movable bell or mullle type furnace herein described is alsorectangular in shape and consists of two 'side walls 5a, two end walls5b, and a roof or crown 5c, all of refractory-material, the bell beinghoused in ametal casing 6. The inside dimensions of the furnace exceed'the corresponding dimensions of the elevated platform, as shown in Fig.1, the lower ends of said furnace being shaped to correspond with thebase 2, and

-the lowermost edge of the furnace resting upon the floor level aboutthe foundation when in operating position.

' A plurality of vertically extending tubes '7 are positioned along thetwo parallel side walls 51,. the upper ends thereof being reducedsomewhat in diameter and protrude outwardly through the crown 5, dampers8 being present in each of said tubes: Said tubes rI are maintained inrigid relation interiorly of the furnace by means of hooks 9 whichembrace said tubes, the Shanks of said hooks extending outwardly throughthe side walls of the furnace and being fastened by nuts.

The lower ends of said vtubes 'l are connected to and supported by elbowjoints l0, the opposite right angle end of each elbow being connectedtoa sleeve 11 which extends in length throughout the thickness of thefurnace walls, terminat-I ing exteriorly of the furnace wall. Each ofsaid sleeves 11 is composed of a hollow tubular casing lined withrefractory or insulating material. As shown in the drawings, the elbowsl0 rest upon a ledge 12 formed interiorly of the furnace wall adjacentthe bottom.

Firing into each of the sleeves 11, which latter, in conjunction withthe elbows 10, serve as combustion tunnels, is an individual gas or oilburner 13, supplied with fuel through the manifolds 14 carried by thefurnace, as by means of the brackl ets 15. A valve 16 is provided witheach burner whereby the operation of the latter may be regulated. y

In practice, the material 3, as steel sheets, to

. bev-treated is stacked upon the raised base 2 and thel furnace is thenlifted and placed over and about the base 2 by means of an overheadlifting crane, supporting eyes 17 being provided at opposite corners onthe furnace to facilitate moving.

When lowered about the base 2, the outwardly and downwardly extendingannular skirt 18,

lief

lthe inside of thefurnace'from the atmosphere,

as depicted in Fig. 1. The burners 13 are then ignited and the burningof the fuel'in the vsleeves 11 and elbows 10 results, of course, in thecrea-- 1y fired unta such time es the material is brought .up to therequired temperature and there maintained for a predetermined period oftime.v f

when the heating cycle is eomp1eted, the burners are closed and thefurnace'may'be cooled by passing air through the tubes, or itmay becooled solely by loss Yof heat through radiation, after which thefurnace is lifted and removed to permit removal of the material, afterwhich the operation may berepeated. e I 4 y Upright pins 20 may bestatlonarily xed to the oor and project upwardlytherefrom at oppositesides of the base so as' to receive thereabout loops or eyes 19extending outwardly from the furnace, this arrangement affording meansfor guiding the latter to correct seating position with respecttothebase. e From the above description it will be noted that thefurnace described provides a structure in which annealing may take placeefficiently. economically and with considerable saving of time. It willalsobe observed that the construction presented aords an annealingchamber in which substantial variations in temperature at differentpoints of the furnaceis eliminated. Under exi isting methods, the top ofthe furnace or the pack is always hotter than the bottom, thisdifference at times amounting to as muchv as 500 F. This conditionproduces sheets. that are not uniform in anneal, many beingover-annealed and 'many having to be returned for further annealing. Onereason for the diierenceintemperature in the top and bottom of the packor furnace is due to.

the concentration of weight or mass that must be heated adjacent thebottom. Inbox annealthe sheet supporting plate-like tray, ball rollers,and sand seal are located at the bottom, and these elements alonellcontribute one-fourth to one-half of the total mass to be heated toannealing temperature. Too, as is well. known in the art, it isdifficult to force and maintain heat adjacent the bottom of any furnace.

Due to the fact that the ame fired from the yburners 13 of the hereindescribed structure is While I havev herein described the furnace asbeing of rectangular-shape, it will be understood that other anddifferent shapes may more readily be adapted for certain purposes. Forinstance, a circular shape may be utilized for the annealing of coilsand the like. Y f

It is thought that the construction and operation of the furnace and thefunction. of its various elementswill readily be understood from theyinterfree v f foregoing description. Further, while I have describedthe invention more or less in detail, it will be understood that I donot limit myself to Adetails of construction and arra ement of parts`except as may be required by4 a air interpretation of the terms of theappended'claims.

What is claimed isze y l. In an annealing furnace, a base, a bell sideand end walls and a roof movably mounted on the base, a series ofvertical heating tubes in vthe bell disposed along each side wall ofthelatter andhaving upper open ends extending through the roof and havinglateral portions at ,theirI lower ends ppening through the side walls atthe lower parts of the latter, and a manifold connected to each sidewall of the bell and having a series of burners, one for each tube,which burners are in register with the open ends of the lateral portionsof the tubes,'the upper ends of the tubes being attenuated and havingdampers disposed exteriorlof the roof,

2. In an annealing'furnace, abase, a bell having side and end walls anda roof movably mounted on the base, aV series of vertical heating tubesin the-bell disposed along each side wall of the latter and: having`upper open ends extending through the roof and having lateral portionsat their lower ends opening through the side walls at the lower parts ofthe latter, and a manifold connected to each side wall of the bell andhaving a series of burners one for each tube which burners are ,inregister with the open ends of the lateral portions of the tubes.

3. In an annealing furnace, abase, a bell having side and end walls anda roof cooperable with the base, a series of vertical heating tubes inthe bell. disposed along each side wall of the latter andv having upperopen ends extending through the roof and having lateral portions attheir lower ends opening through the side walls at the lower parts ofthe latter, and a series of burners one for each tube which burners arein register with the open ends of the lateral portions of the tubes., v

- 4. In an annealing furnace, a base, a bell cooperable with the base, aseries 'of vertical heating tubes in the bell disposed along oppositesides of thel latter and extending substantially throughout the heightof the bell, and having portions extending through said sides of thebell, and means for supplying heat to each of said portions of thetubes.

5. In an annealing furnace, a base, a bell cooperable withv the base, aseries of vertical heating tubes in the bell disposed along oppositesides of the latter and extending substantially throughout the height ofthe bell, and having portions extending through said sides of the bell,and a burner for each tube in register with said portions thereof.

6.*In a heat treating furnace, a base, a bell located over said base, yaseries of vertical heating tubes inthe bell disposed along each sidewall of the latter and having vtheir upper ends extending exteriorly ofthe bell adjacent the roof of the latter, and a series of gaseous fuelburners, one foreach tube, whereby each tube may be individually fired.

.7. In a furnace, the combination with a'heatling chamber and a hearththerefor, a plurality distance above said hearth, and a gaseous fuelburner located in the lower end of each of said tubes whereby each tubemay be independently red. i

8. In a furnace, a base, a movable bell cooperof the tubes.

9. In a furnace, a heating chamber, a series of vertically disposedheat-radiating tubes arranged along the walls of said heating chamber,and having their lower portions extending exteriorly of the furnaceadjacent -the hearth, a gaseous ,fuel burner for each tube in registerwith each of said portions whereby controlled heat v treatingtemperatures may beindividually intro. duced into each of said tubes.

WILSON.

